Old Mechs
by Tigressa101
Summary: (Bayverse) King Kronos and Sentinel Prime have a lot in common though their choices render completely different. Despite this, they like to spend time with each other, and not in the way you'd expect. OC/Sentinel Prime


**AN: Warning, this fic contains slash and a very dense version at that. To be honest, I don't know what I was thinking with this but I did it, so I'm still posting it.**

**For those of you who do not know what my OC, King Prometheus Kronos (King Kronos), looks like, he's pretty much a modified black Precursor Robot (Jak & Daxter) with white tribal designs, eyes, and waist. He's a dragon so remember, he has a tail and wings. Have fun imagining this!**

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><p>Sentinel purred as he felt claws trace over sensitive nodes on his chassis. He sat on his master's lap with his own servos gliding over the big mech's shoulders, and his legs wrapped around the strong, masculine white waist. He arched his back as the Precursor mech's teeth caressed his neck cables.<p>

Their relationship was complex but thankfully, Queen Kiara approved of it since she felt he needed someone to "play" with when she was gone for a long time. What began as just a friendly encounter the first time turned into something more. The King, with his giant, broad physique, dominated the Prime but occasionally let the fire truck be the alpha bot.

Another thing that was complex was the size difference. King Kronos was roughly fifty foot three when Sentinel was just thirty-five foot ten. It made their endeavors together somewhat hard but they managed just the same. One time, they even let Optimus join them which forced the dragon to let them overtake the pleasurable situation since the two Primes' heights would make up for the gruesome stature problem. Mostly, however, it was just the elder Sentinel Prime and Prometheus Kronos.

Kronos gave a toothy smirk as he heard his lover cry out in ecstasy when he bit down on the mech's shoulder. After drawing Energon from the seeping mark, he licked it clean which luckily his saliva was a sort of gel that could prevent more fluid from leaking out. He then brought his tongue up to the Prime's faceplates before leaving a trail of wetness on the Bot's cheek. His playmate didn't fight against it and accepted the unusual affection with a chuckle.

The King had to fight off the urge to moan when Sentinel began grinding against his lower plating, very eager to awaken his arousal it seemed. He couldn't help but pant as the friction drew him to a greedy haze. Growing stir-crazy by the smaller mech's movements, his spikes rippled down his spine impatiently, a warning that he was so close to just taking the red mech here and now.

Sentinel was apparently enjoying his newfound supremacy over the dragon. He could see the King attempting to resist his inducement. He remembered when the dragon was in this state, he could be tamed, molded to do whatever the Prime wished. It was one of the only times Kronos could be vulnerable.

Prometheus finally couldn't take it anymore. With a click and metal shifting below his abdomen, he released his pressurized spike that touched the fire truck fervently. The slits in his waist discharged steam to counter some of the compression inside him. He knew the mech straddling him noticed how his wings' talons were now digging into the walls beside him and his tail was ridged, swirling into a tight coil. His congenial provocation was showing far beyond his control which Sentinel found ironic since his master's species of Transformer were known for "limitless" patience.

The Prime brought his legs to sit under him on Prometheus' white-tribal covered thighs before teasing the pulsing appendage. In the corner of his optics, the dragon's tail twisting madly at the excitement within its owner.

"Is something 'wrong', your Majesty?" Sentinel seductively hissed, "You look tense. If only you could relinquish the feeling you have inside and take what you want without any restraint."

Kronos swallowed hard, the "Adam's apple" in his throat wobblingly moving up and down with dithering pain. He gave a quick roar of approval before leaning into the Prime's touches. "You have no idea," the King groaned.

With that, Sentinel opened his own interface panel and gloated at his valve which had caught the attention of the black and white dragon. He observed how Kronos shifted his neck longer to get a better look at the glorified entrance; techno-organics amazed him when they could do things his species couldn't.

"Ah, ah, ah, no!" The fire truck slapped his snout away before it could get too close to his opening.

He forced Prometheus to rest back against his chair as he stroked his master's spike. Reluctantly, Kronos obeyed. The Prime slid his glossa over the tip to see what reaction he would get. He heard Kronos' breathing hitch and his cooling fans kick to their maximum setting, almost like they knew what would happen next and wanted to be prepared.

Finally, Sentinel put the erection into his mouth after a couple minutes of teasing. The claws that belonged to the King scraped on the armrests of his throne as the red mech performed his oral treatment. A series of low growls, barks, and moans erupted from the large mech.

A few times the Prime gagged because the appendage was too big to fit in him, and sometimes it would go deeper than anticipated. While he was pleasuring the dragon, he rubbed his own passage and occasionally played with his spike as a reward for his efforts. He was as turned on as Prometheus but he knew he'd always be the one being pounded into despite the fact he actually managed to flip the table in his favor once.

"Oh…a-ah, S-Sentinel!" Kronos hoarsely stuttered.

The King felt heat surging through his body too fast for his systems to control. By now, the armrests were just four slices of metal barely hanging onto one another. The same could be said for the floor that now had six marks engraved in it from both feet. With a good final pump, Prometheus overloaded with a loud bellow and ejected his transfluid into the fire truck's orifice.

Sentinel swallowed the lubricant easily before positioning himself over the erotic spike. He stuck two fingers inside himself to get ready for the large appendage that would breach his delicate entrance. When he felt set, he slid down on the erection, taking in its size that sent waves of bliss swarming through his mainframe.

Kronos was already lost again, his servos propped against his chest like a dog. He was waiting for the Prime to take charge. He got his wish instantly, for the red mech began rocking into him at a steady pace, taking it to the hilt which made Prometheus' vision blur with static. He soon joined their dance with a hard plunge.

The bot felt very tight, almost cutting off circulation in his member that had now been numbed with warmth. His breathing and spark-beat quickened with each thrust given. He couldn't stop himself; he was off the edge and couldn't turn back now.

The Prime kept his balance by using the dragon's legs for support, rolling his hips to match the massive thrusts his master was countering him with. He was struggling to keep himself from going overboard too fast, but each time the spike pounded into him, his systems would send warning signals of overheating and him holding too much pressure. That was the point, was it not?

He wished his system would realize the more pressure saved up meant a stronger, heavenly orgasm. Whether Kronos was collecting the same warnings or not, he didn't know but by the glare of the large mech's optics, he was fighting the same programming.

Sentinel reached up to grab the King's snout and pulled him into a forceful kiss, intertwining his glossa with Prometheus'. The kiss ended as he arched once more into the appendage inside him. Close to an overload, he wrapped his arms around the sturdy, thick neck of the dragon and rapidly slammed himself down, not wanting to delay his needs anymore.

Kronos realized this and had to agree; he couldn't take it any longer either. He placed his hands on the fire truck's hips to ensure Sentinel would overload with him.

Together, they rammed each other until both reached their peaks. The Prime buried his head into the dragon's chassis while Kronos continued to exhort more pleasure as they overloaded. The red mech gave a sheer cry of desire as his valve clasped around the thick member. He felt the King's hot transfluid stuff his opening to the point where it began to leak out onto his master's thighs.

When the orgasm died down, both didn't move from their spots. They just sat there, relishing each other's company.

Kronos panted between words as he spoke up, "I…think…I will…have to…explain…this to…my wife."

"Eh…I…don't blame…you. Optimus…would…want to…know what happened," Sentinel smiled.

"Do you think…they'd enjoy the story?"

"Probably…considering how ballsy…both your mate and my successor seem to be. They'll like it…alright."

Prometheus couldn't contain a smirk.

As Sentinel got off Kronos' spike, the King began licking his face as if to say "thank you". When Prometheus ended his animal-like stream of kisses, both started cleaning themselves and closed their interface panels. After all, they didn't want to wander back to the N.E.S.T base with their equipment hanging out and evidence of their affair for all but Optimus and the Queen to see.

A few minutes passed before they were ready to return. Kronos lowered a wing to offer the Prime a ride. Sentinel took the proposition immediately since they left together with him riding on the dragon's back. He flashed another smile at Kronos before the King began sprinting back, occasionally flying to give his wings some exercise.

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><p><strong>AN(2): Yeah, not your average DOTM Sentinel fic, huh? Again, I do not know what I was doing when I typed this. If it was hard to picture, I understand. Hope you enjoyed this nutshell-of-a-pairing!<strong>


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